What's unique (so far) about Larrabee is that it's entirely made up of x86 processing cores. The Larrabee is likely to have 32 x86 processing cores. Here's a surprise: These processing cores are based on the design of Pentuim P54C, a 13+ year old x86 processor. This processor will be miniaturised to the 45nm fabrication process, they will be assisted by a 512-bit SIMD unit and these cores will support 64-bit address. Gelsinger says that 32 of these cores clocked at 2.00 GHz could belt out 2 TFLOPs of raw computational power. That's close to that of the upcoming AMD R700. Heise also reports that this GPU could have a TDP of as much as 300W (peak). ~(src: TechPowerUp)

If the GPU is that freaking huge... I imagine heat would be an issue for overclocking. Add some subzero cooling or even water, bet that chip will overclock well... assuming the power consumption increase doesn't melt the PCB first.